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Biomedical subjects

R Yarom

Publications and source records attributed to R Yarom.

At least 55 records · Page 3Linked to original sources
PubMed1984

"Rimmed vacuole myopathy" sparing the quadriceps. A unique disorder in Iranian Jews.

Nine cases from 4 different Iranian-Jewish families presented with generalized muscular weakness. Quadriceps muscle was the only leg muscle which retained its normal power and function even in advanced cases. Biopsies from severely involved muscles revealed a typical "rimmed vacuole myopathy" while the quadriceps and deltoid showed minimal changes. CK levels were normal or moderately elevated and the EMG pattern suggested an underlining neurogenic disorder. The possible neurogenic character of this autosomal recessive disorder is discussed with relevance to the rimmed vacuoles.

Adult↗
PubMed1984

T-2 toxin effect on bacterial infection and leukocyte functions.

The effects of T-2 toxin on bacterial infection and leukocyte function and structure were examined in vivo and in vitro. Rats were innoculated with staphylococci after pretreatment with or without T-2 toxin. The T-2 pretreated rats failed to mount a cellular response to the bacteria. Blood and bone marrow cells were markedly suppressed by the T-2 toxin, the myeloid series being the most affected. In vitro studies with human leukocytes showed that small, nonkilling doses of T-2 toxin inhibited chemotaxis, chemiluminescence stimulated by bacteria, and phagocytosis of bacteria. It was concluded that this inhibition may contribute towards sepsis and rapid onset of death in T-2 toxin poisoning.

Animals↗
PubMed1984

The effect of T-2 toxin on human platelets.

Human platelets were incubated with T-2 toxin, the most toxic component of Fusarium fungi, at doses of 5 to 500 micrograms/10(9) platelets. A dose-related inhibition of platelet aggregation and release of dense bodies (these consist mainly of serotonin-containing granules) were observed. A change in membrane permeability in the absence of shape changes was also demonstrated by a heavy metal impregnation technique. There was no correlated inhibition of thromboxane synthesis or significant alterations in platelet calcium content. The microtubular system was also unaffected. Suppressed platelet aggregation may contribute to the lethal hemorrhagic phenomenon associated with intoxication by fusarial toxins in man and animals.

Blood Platelets↗
PubMed1983

Platelet abnormalities in muscular dystrophy.

Platelets which have complex membranes and calcium shifts similar to those in muscles were investigated in 14 patients with muscular dystrophy and 20 suitable controls. In 4 Duchenne and one limb-girdle dystrophy aggregations were done and found to be depressed with adrenaline and ADP. Electron microscopic and chemical examinations revealed an increased number of dense bodies, changed permeability and/or binding of cations and elevated intracellular calcium in all the 9 cases of Duchenne dystrophy while the 2 limb-girdle and 3 myotonic dystrophies varied. A two phase polymer separation system applied to fixed platelets of all patients and controls showed no abnormality of surface negative charge.

Adolescent↗
PubMed1983

X-ray microprobe analysis of platelets. Principles, methods and review of the literature.

Platelets are well suited to X-ray microanalysis as there is no need for chemical fixation or sectioning, and the concentrations of calcium and phosphorus are above 10(-3). The principles of the technique, the methods of specimen preparation, instrumental conditions during analysis and ways of quantitation are described. This is followed by a review of published reports and a brief summary of the author's own work in the field.

Blood Platelets↗
PubMed1983

Muscle regeneration and transplantation enhanced by bone marrow cells.

This work was undertaken in an attempt to improve the usually poor results of muscle regeneration and grafting in cases of muscle injury. Since bone marrow cells markedly increase myogenic growth in vitro (in Millipore diffusion chambers), we added autogenous and isologous bone marrow cells to minced muscle grafts or to sites of excised muscle in rats. In each case the opposite side was left without added marrow cells, to serve as a control. The results showed that addition of bone marrow produces more extensive muscle regeneration with little fibrosis. The myogenesis-stimulating and antibacterial properties of bone marrow cells warrant further study, aiming towards clinical application of the method.

Animals↗
PubMed1983

T-2 toxin-induced pathology in the hearts of rats.

T-2 toxin is the major lethal component of several Fusarium fungi implicated in diseases of man and animals. We report here on the histological and ultrastructural changes in hearts of rats given i.p. single large or repeated small doses of T-2 toxin. One, 2 and 3 days after a single large dose, there were lesions in most hearts. They consisted of interstitial oedema, focal cellularity and damage to single or groups of myocytes. The small intramural coronaries were constricted, swollen and sometimes disrupted. After 7 days, most of the changes subsided. In rats killed 1 or 2 months after the last of 10 daily injections of T-2 toxin, cardiomyopathy-like changes were seen with hypertrophy, focal fibrosis and abundant cellularity especially in the subendocardial regions of the left ventricle. The findings, although non-specific, indicate that T-2 toxin is cardiotoxic.

Animals↗
PubMed1982

Studies of platelets with heavy metal impregnation techniques.

Various methods of heavy metal impregnations were performed on human platelets. The optimal technique consisted of glutaraldehyde fixation, incubation in warm uranyl acetate at a pH of 3.5, followed by a double solution of lead and copper, and finally overnight immersion in cold osmium tetroxide. Semi-thin sections, viewed at 90 kV, revealed three types of platelets: (1) 'reticular' cells, with a prominent tubular network and very dark granules in a pale cytoplasm; (2) 'dark' cells, with an electron-dense cytoplasm; and (3) 'pale' cells, with microvesicles and non-staining granules. Pre-treatments with EGTA, aspirin and various platelet activators altered the appearances and proportions of the three cell types. A cell-partitioning two-phase polymer system showed that the sub-grouping is related to surface membrane properties, the cells retained in the top phase being exclusively type 2 'dark' cells. The changes in cell type distribution produced by activation show that metal impregnation may be a useful method for studying structure-function correlations in platelets.

Aspirin↗
PubMed1982

Enhancement of human muscle growth in diffusion chambers by bone marrow cells.

Samples of minced human muscle were cultured in millipore diffusion chambers incubated in the peritoneal cavities of mice. In about half the chambers the minced muscle samples were mixed with autogenous bone marrow cells which lead to improved myogenic growth. A similar but less marked effect was produced by mononuclear cells from the patients' blood. No growth enhancement occurred when the muscle and marrow cells were separated by a filter in double chambers. In addition to accelerated myogenesis, the chambers with added bone marrow cells had a much lower incidence of infection. This work may have practical clinical implications for the treatment of muscle injuries. Local implantation of autogenous marrow cells (+/- minced muscle) may prove useful in improving myogenic regeneration.

Adolescent↗
PubMed1982

Platelet studies in patients with hypertrophic cardiomyopathy.

Because of a shared abnormality of platelet and muscle in some neuromuscular diseases, platelets were investigated in five cases of hypertrophic cardiomyopathy, a disease likely to be primarily myogenic. Morphometric and chemical differences from normal were found consisting of increased cell size, decreased phosphorus concentrations and increased permeability to cations. The findings suggest membrane and energy metabolism aberrations.

Adult↗
PubMed1982

Contractile protein studies on platelets from patients with idiopathic scoliosis.

Measurements of total proteins, myosin, actin, actin-binding protein, and ATPase activity of myosin were examined in platelets from patients with idiopathic scoliosis and from healthy individuals. Abnormalities in the distribution of total and contractile proteins were revealed after fractionations. The insoluble fraction of the patients' platelets had a higher, and the cytosol fraction had a lower than normal protein content. Similar differences were observed in the specific activity of myosin ATPase. These findings show that in patients with idiopathic scoliosis platelet defects exist and that their study might be useful in research of the disease.

Actins↗
PubMed1981

Platelet heterogeneity and dense tubular system changes on activation.

Platelets impregnated with heavy metals appeared as 3 distinct morphological types: 'reticular' cells with a polygonal dense tubular network and stained granules, dark metallophilic cells, and pale metallophobic cells with microvesicles and non-staining granules. On stimulation, type 1 cells decreased while type 3 cells increased, suggesting that with activation dense tubules break up into microvesicles and granules become metallophobic. In the type 2 cells a different functional mechanism may exist.

Adenosine Diphosphate↗
PubMed1981

Diffusion chamber cultures of muscle from patients with scoliosis.

Explants from paraspinal muscles of patients with scoliosis were cultured in Millipore diffusion chambers placed in peritoneal cavities of mice. Three and four weeks of incubation produced a predominantly myogenic growth. Cell counts done on paraffin sections and on dissociated cells from the chambers showed that explants from the concavity of the spinal curvature grew better than those from the convexity. Since cells from injured muscles, when transplanted or cultured, are known to grow better than those from healthy control tissue, these findings support our previous morphologic observations that in idiopathic scoliosis concave muscles are more involved by the disease process. Secondary subculture of the chamber contents by conventional methods produced myotubes within one to two weeks. The relative ease of diffusion chamber muscle culture should make the method useful to laboratories that are not specifically equipped for tissue culture work.

Adolescent↗